There are a number of characters still alive in the comic book that are dead on the TV show and vice versa. There are even characters who never existed in the comic book that are among the most popular on the series.
For what it's worth, here's where Rick stands in Kirkman's comic book: He's lost a wife, a daughter and numerous friends. He's missing a hand, has battled the ruthless villain Negan and is currently trying to fight off a group of survivors known as The Whisperers who where zombie skin on their faces.
Needless to say, Kirkman's comic is a thrill ride. So it's not that shocking for him to have said, "Rick could go at anytime," back in 2012, because that's the nature of a comic book set in a world ruled by the dead. In the Daily Dead interview, Kirkman went on to say Rick would stick around for a long time, but he thought Carl could carry the book.
As a longtime fan of the comic book, I've long foreseen a future where Rick dies and Carl takes the reigns as the book's main protagonist. But I don't see how that would work on the TV show, at least not yet.
Carl's character isn't as compelling on TV as he is in the comic book. Furthermore, while Kirkman has put various characters on the cover of his comic, there isn't a major AMC promo or trailer for "The Walking Dead" that doesn't have Rick Grimes front and center.
If I had to choose a scenario where Rick dies on the TV show, I suppose he goes out Walter White style in the finale, leaving the world with his son and daughter in a better place. But even that seems like a bit of a stretch.
Until "The Walking Dead" TV show ends, which won't be for at least a few more seasons, Rick Grimes will remain its central focus, whether Kirkman tries to suggest otherwise or not.